A brief survey is made to highlight the recent interests in positron, positronium and antimatter physics. Positron is the first antiparticle observed which was predicted by Dirac. Positronium is itself its antiparticl...A brief survey is made to highlight the recent interests in positron, positronium and antimatter physics. Positron is the first antiparticle observed which was predicted by Dirac. Positronium is itself its antiparticle and bi-positronium molecule is recently observed in laboratory which was predicted by Wheeler in 1946. The simplest antiatom i.e. antihydrogen is observed in the laboratory and the process to achieve the stable confinement of antihydrogen within the trap are in progress to test the standard model.展开更多
With the advent of the ability to create and study antihydrogen, we think it is appropriate to consider the possibility that antiphotons might not be identical to photons. First of all, we will look at the experimenta...With the advent of the ability to create and study antihydrogen, we think it is appropriate to consider the possibility that antiphotons might not be identical to photons. First of all, we will look at the experimental evidence concerning multiple neutral pions and multiple photons. Because of its internal structure, the neutral kaon is not identical to its antiparticle. We will consider internal structures for the neutral pion and photon for which the antiparticle differs from the particle. Interestingly, the antiphoton thus created from neutrinos does not interact with electrons because its neutrinos have the wrong helicity.展开更多
The ATRAP (antihydrogen trap collaboration) at CERN (European organization for nuclear research) has developed a completely new, larger and more robust apparatus in the second experimental zone. The antiproton annihil...The ATRAP (antihydrogen trap collaboration) at CERN (European organization for nuclear research) has developed a completely new, larger and more robust apparatus in the second experimental zone. The antiproton annihilation detector system consists of 10 layers of scintillating fibers, counts the antihydrogen atoms and determines the annihilation vertex of the atoms. This diagnostic element will allow to optimize the production of cold antihydrogen sufficiently to permit the optical observations and measurements. Using this new apparatus thousands of antihydrogen atoms have been produced within a combined Penning-Ioffe trap. These observed antihydrogen atoms resolve a debate about whether positrons and antiprotons can be brought together to form antihydrogen atoms within the divergent magnetic fields of a quadrupole Ioffe trap.展开更多
A renewed antiproton annihilation detector system has been developed for the ATRAP (Antihydrogen Trap Collaboration) experiment at CERN (European Organization for Nuclear Research). It counts the antihydrogen atoms an...A renewed antiproton annihilation detector system has been developed for the ATRAP (Antihydrogen Trap Collaboration) experiment at CERN (European Organization for Nuclear Research). It counts the antihydrogen atoms and determines the annihilation vertex of the atoms. This diagnostic element will allow to optimize the production of cold antihydrogen sufficiently to permit the optical observations and measurements. Extensive Monte Carlo simulations concerning the detector system have been developed. Different event generators as well as different geometry representations were established and evaluated. Real-time measurement with the detector system was performed and the results are calibrated via the Monte Carlo simulations.展开更多
文摘A brief survey is made to highlight the recent interests in positron, positronium and antimatter physics. Positron is the first antiparticle observed which was predicted by Dirac. Positronium is itself its antiparticle and bi-positronium molecule is recently observed in laboratory which was predicted by Wheeler in 1946. The simplest antiatom i.e. antihydrogen is observed in the laboratory and the process to achieve the stable confinement of antihydrogen within the trap are in progress to test the standard model.
文摘With the advent of the ability to create and study antihydrogen, we think it is appropriate to consider the possibility that antiphotons might not be identical to photons. First of all, we will look at the experimental evidence concerning multiple neutral pions and multiple photons. Because of its internal structure, the neutral kaon is not identical to its antiparticle. We will consider internal structures for the neutral pion and photon for which the antiparticle differs from the particle. Interestingly, the antiphoton thus created from neutrinos does not interact with electrons because its neutrinos have the wrong helicity.
基金Supported by the NSF (Grant No. 0306308) AFOSR of the US, the BMBF, MPG and FZ-Juelich of Germany, and the NSERC, CRC, CFI (Grant No. 3756) and OIT of Canada
文摘The ATRAP (antihydrogen trap collaboration) at CERN (European organization for nuclear research) has developed a completely new, larger and more robust apparatus in the second experimental zone. The antiproton annihilation detector system consists of 10 layers of scintillating fibers, counts the antihydrogen atoms and determines the annihilation vertex of the atoms. This diagnostic element will allow to optimize the production of cold antihydrogen sufficiently to permit the optical observations and measurements. Using this new apparatus thousands of antihydrogen atoms have been produced within a combined Penning-Ioffe trap. These observed antihydrogen atoms resolve a debate about whether positrons and antiprotons can be brought together to form antihydrogen atoms within the divergent magnetic fields of a quadrupole Ioffe trap.
文摘A renewed antiproton annihilation detector system has been developed for the ATRAP (Antihydrogen Trap Collaboration) experiment at CERN (European Organization for Nuclear Research). It counts the antihydrogen atoms and determines the annihilation vertex of the atoms. This diagnostic element will allow to optimize the production of cold antihydrogen sufficiently to permit the optical observations and measurements. Extensive Monte Carlo simulations concerning the detector system have been developed. Different event generators as well as different geometry representations were established and evaluated. Real-time measurement with the detector system was performed and the results are calibrated via the Monte Carlo simulations.
